Abstract
This review provides an outline of the “high-efficiency/high-quality protein crystal formation system” project. Precise determination of protein structures provides significant information for R&D on drugs and enzymes. Protein crystals of high integrity grown with high efficiency can accelerate such R&D. At present, a condition suitable for a certain protein crystal growth can only be found after several thousands of different conditions are examined by changing various parameters such as solvents, coexisting materials, temperature, pH and so on. It is considered that the convection of solution prevents the formation of good-quality crystal. Therefore, the control of gravity force effect through large magnetic force may be one of the potential parameters for protein crystal growth because it should contribute to suppressing the convection. To exert large magnetic force on protein solution or crystals equivalent with gravity force, high magnetic fields using a superconducting magnet are required. Observation of the crystallization process is important for efficient crystal formation, but it is difficult to carry out in-situ optical observation inside the superconducting magnet bore due to the existence of the high magnetic field. To facilitate efficient protein crystal growth under magnetic force, we developed a microscopic optical observation apparatus for multiple samples placed in a high magnetic field. The system consists of a superconducting magnet, crystallization plates and an optical periscope. The superconducting magnet used for this system is a high magnetic force generation type. The developed crystallization plates can contain 24 different protein solutions and can be stacked on each other. The 3D controllable periscope is made mainly from feeble magnetic materials that can be operated in high magnetic fields.
